TPM systems have been used in a variety of vehicles, and in some cases are mandated by government regulations, vehicle manufacturer specifications and/or other requirements. For example, the Transportation Recall Enhancement Accountability and Documentation Act (also known as the TREAD Act) is a U.S. law that requires most new vehicles under 10,000 pounds of gross vehicle weight to be equipped with a TPM system that can alert a driver when the pressure in one of the tires falls below a certain level.
A conventional TPM system typically includes a battery-powered tire pressure sensor capable of radio frequency (RF) signal broadcast located at each vehicle wheel and a signal receiver located elsewhere on the vehicle. The tire pressure sensors transmit information regarding tire pressure and/or other readings over a one-way wireless link that connects the tire pressure sensors with the vehicle-mounted signal receiver. Typically, the one-way wireless link uses a fixed communications protocol and a fixed modulation scheme.